138120869 has 4 divisors (see below), whose sum is σ = 146245644. Its totient is φ = 129996096.

The previous prime is 138120839. The next prime is 138120877. The reversal of 138120869 is 968021831.

138120869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 85340644 + 52780225 = 9238^2 + 7265^2 .

It is a cyclic number.

It is not a de Polignac number, because 138120869 - 2¹² = 138116773 is a prime.

It is a super-2 number, since 2×138120869² = 38154748906630322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138120839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4062362 + ... + 4062395.

It is an arithmetic number, because the mean of its divisors is an integer number (36561411).

Almost surely, 2^138120869 is an apocalyptic number.

It is an amenable number.

138120869 is a deficient number, since it is larger than the sum of its proper divisors (8124775).

138120869 is an equidigital number, since it uses as much as digits as its factorization.

138120869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8124774.

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 138120869 is about 11752.4835247704. The cubic root of 138120869 is about 516.9157528521.

The spelling of 138120869 in words is "one hundred thirty-eight million, one hundred twenty thousand, eight hundred sixty-nine".